akruit :
Because the HD from my pc is formatted I copied Vista on an Ext.HD via another PC. How can I make the pc working again with the copy of Windows Vista on the ext.HD?
Whenever I want to install any operating system from Vista to Windows 10, I simply copy the contents of the ISO file onto an USB stick and that's it, you're ready to install.
Just go into your BIOS, set the USB Stick as the first boot device, reboot and then it'll start installing.